Explosively actuated under water riveting and punching or like apparatus



P. COX

July 11, 1939.

EXPLOSIVELY ACTUATED UNDER WATER RIVETING AND PUNCHING OR LIKE APPARATUS Filed May 21, 1937 Patented July 11, 1939 PATENT OFFICE EXPLOSIVELY ACTUATED UNDER WATER RIVETING AND PUNCHING OR LIKE AP- PARATUS Percy 00:, Kent, England Application May 21, 1937, Serial No. 144,106 In Great Britain April 1, 1936 3 Claims.

This invention relates to exposively actuated apparatus for driving a projectile such as a bolt, rivet, or punch into or through a resistant body, and is particularly concerned with apparatus for use under water in performing operations of the above character incidental to the salvage and repair of sunken ships, although the apparatus may be used for other purposes. An apparatus of the general kind referred to its described in British Patent Specification No. 141,406 and comprises means for causing delay in the movement of the projectile after the propelling charge has been fired, and a projectile having a separable rear partwhich remains in the barrel and is arrested by suitable means provided for the purpose.

It has been found that the presence of an enclosed or laterally confined column of water, even of relatively short length, within the barrel of such an apparatus gives rise to serious diiiiculties in practice as owing to the inertia of the mass of water the pressures set up by impact of the projectile are exceedingly high and may damage or even destroy the apparatus. It is desirable moreover that the means for arresting the separable or driving part of the projectile should be located at a definite and predetermined distance from the muzzle of the projection barrel, this distance depending upon the length of the projectile and its amount of penetration, and its provision being necessary in order to ensure that when the apparatus is fired while being held against a resistant body the projectile will penetrate the body to some extent before the separable part is arrested, by which means the recoil is-sufflciently reduced to allow of the apparatus being held in the hand.

The main object of the present invention is to provide improved apparatus which fulfils these requirements while at the same time overcoming thezdiiiiculties referred to above.

According to the invention an apparatus of the kind .referredto comprises a projection barrel having means for arresting a separable or driving part of a projectile therein and from which water is excluded, and a part or extension of the barrel adapted to determine the relation between said arresting means and a resistant body when the apparatus is in use, which part or extension is formed or arranged to avoid enclosure of a column of water therein such as would give rise to unduly high pressures when ejected by the projectile.

The invention also consists in apparatus of the kind referred to in which the barrel has a part extending beyond the means for arresting the separable portion of the projectile, and means is provided either for excluding water altogether from said extension or for dissipating pressure I created therein by the passage of the projectile.

One form of the means for excluding water from the barrel or its extension comprises a seal of easily rupturable material secured at or near the extreme end thereof. The material may be rubberized fabric, fibre or other suitable com-' position and may be in the form of a disc or plug as desired.

In one convenient arrangement the arresting means for the separable part of the projectile comprises a metal disc clamped between the end of the barrel and a tubular extension piece, and a sealing disc is secured to the end of said extension piece by means such as a threaded ring. The extension piece referred to preferably has a bore of smaller diameter than that of the barrel, allowing for the passage of the front portion of the projectile but opposing the separable portion thereof.

Alternatively the part or extension of the barrel beyond the arresting means may be open to the entry of water and one or more lateral openings or ports are provided for dissipating pressure. These ports extend from the extremity of the said part or extension to a point at which water is excluded. Thus according to one arrangement which is adapted for use with relatively long projectiles, the arresting disc is held in place by a threaded cap which carries toward its outer end a rupturable sealing disc, and beyond the sealing disc the walls are cut away to form a part of lateral ports.

According to another arrangement the separate sealing element is omitted, the arresting disc being placed at the end of the barrel proper and held in place by a threaded cap which is formed with lateral ports. This form is suitable for relatively short projectiles, for example those in the nature of punches which are intended to be driven completely through a metal plate orother body. The threaded caps which hold the arresting discs in place may be made in various lengths to suit different sizes of projectile.

Where a watertight seal is arranged at the extreme end of the barrel extension the sealing element may have a boss formed thereon which may be used in locating the apparatus, as for example when it is desired to drive a bolt into an existing hole.

The invention will be best understood from the following description of certain preferred modes of carrying the same into effect. considered in apparatus according to Figures 1 and 2;

Figure 4 is a sectional view of an alternative form 01' water sealing element;

Figure 5 is a longitudinal section of the muzzle portion of a modified form of apparatus conv structed in accordance with the invention, show- Figure '1 is a longitudinal section of the muzzle portion of another modified form of the apparatus Figure 8 is a side view of. the muzzle shown in 5 Figure '7;

Figure 9 is a sectional view of the muzzle of Figure 7 taken on a transverse plane;

Figure 10 is a modified muzzle construction shown in longitudinal section and Figure 11 is an end view thereof;

Figure 12 is a sealing element for use with the muzzle shown in Figure 10.

In carrying the invention into effect according to one convenient mode as applied by way of example to an apparatus of the general character described in British Specification No. 141,406, a barrel is provided with a threaded muzzle extension 2 having a cap 3 threaded thereon. Between the muzzle extension 2 and the barrel I there is interposed a copper or other metal disc 4 and between the cap 3 and the muzzle there is interposed a sealing disc 5 which may be of any suitable watertight material such for example as rubberized fabric, ,fibre or similar composition. It will be noted that the sealing disc 5 is'located closely adjacent to the extreme end of the'cap.

The bore 6 of the muzzle extension is of smaller diameter than that of the barrel i and has a shallow counterbore 1 at the inner end thereof adjacent to the copper disc I.

The projectile in the present instance consists of a tapered bolt l which may be threaded or grooved in any convenient manner as indicated at 9. This bolt is secured by means of a threaded rod III to a hollow steel piston II which contains the explosive charge and isa close fit in the cylindrical bore of the barrel I. The rod I is formed with a portion of reduced strength orcross-section at I2 and is threaded-into a block i3 seated in an enlarged portion of the barrel l. The side walls 01 the piston H are relatively thin particularly towards the rear thereof so that they will make a tight joint with the bore under the pressure of the exploded charge. A thick disc M of copper or other material is placed between the piston II and the block II, which latter has a recess l containing the detonating charge. A small passage (not shown) afiords communication between the recess l5 and the explosive charge in the piston Ii.

The inner end oi the recess [5 is closed by'one or more discs l6 which may be of, thin copper or other suitable material and a block i1 is threaded into the breech end of the barrel for the plates 2 i.

holding the projectile in place. This block provided with an axial hole for the reception of the firing pin. A tubular extension II is screwed to the projecting portion of the block l1 and may be secured by any suitable means within a firing holder is which is provided with a handle 2.. Details of this form of firing holder are given in British Specification No. 141,406 and consequently further description thereof is deemed to'be unnecessary. It will be understood however that this particular construction of holder is to be regarded merely as one convenient mode or device for carrying the apparatus and exploding the charge and that these functions may be eii'ected in a large variety of ways. For example electrical means may be used for firing the charge. In operating the device illustrated in Figure -l the muzzle or the apparatus is placed as shown against a'plate 2| which it may be desired to secure to damaged plating of the submerged hull of a ship for example, and the charge is exploded by depressing the handle 20 to cause the firing pin to enter and detonate the charge in chamber i5.

The consequent explosion of the main charge within the hollow piston it breaks the rod ill at the reduced portion i2 and propels the piston.

The end of the bolt 8 pierces first the copper disc 4 and subsequently the sealing disc 6 and enters The piston il then meets the remaining annular portion of the copper disc 4 and after shearing through the same is brought to rest within the counterbore I, the bolt 8 then parting from the piston by rupture of the rod it as indicated and coming to rest in the plates. so that they are in effect riveted together. Figure.2 shows the bolt entering the plates. The work done in shearing the copper annulus of the disc 4 arrests the motion of the piston Ii and brings it to rest without excessive shock; Should this action be insuflicient to arrest the piston completely the latter will partially enter the-reduced bore 6 of the muzzle and the shearing of the material of the piston itself will eiiectually complete the arrestation thereof. The muzzle is preferably made of tough steel or other suitably resistant material.

It will be appreciated that depending upon the length of the bolt 8 the muzzle 2 must be of a certain length to provide for the arrest of the piston at the proper time having regard to the penetration of the bolt.

The provision of the sealing disc 5 prevents the entry of water into the bore of the muzzle extension 2 and thereby eliminates all possibility. of damage to the apparatus by the creation of excessive pressures within the muzzle.

The plain sealing disc shown in Figures 1 and 2 may be replaced if desired by the sealing element illustrated in Figure 4, the projecting part paratus to be located in the hole without difficulty, an advantage which will'be appreciated when working under water. v

A modified form of the apparatus is illustrated in Figures 5 and 6. In this arrangement the,

, barrel i is provided with a muzzlecap 22 threaded thereon and having a detachable liner 23 the bore 24 of which is of smaller diameter than that.

o! the barrel and has a counterbore 25. A copper disc I is clamped between the liner 23 and the barrel and a sealing disc 5 of suitable watertight material as previously described is clamped between a shoulder of the muzzle cap 22 and the outer end of the liner 23. At the end of. the cap 22 there are provided a pair of lateral ports or openings 26 and the bottoms of these openings are curved inwardly as indicated at 21 to a point closely adjacent the disc 5.

It will be observed that with this arrangement when used submerged although there is a short column of water between the sealing disc 5 and the end of the cap 22, nevertheless this column is open laterally and hence the pressure due to the inertia of the column when it is struck by the bolt 8 will be immediately dissipated through the lateral openings 26 and there can be no danger of creating undue stresses in the cap. The curving of the bottoms of the ports 26 assists in the dispersal of the pressure without shock.

It will be noted that Figure 5 shows the apparatus in use when the bolt has penetrated the plate and is about to part from the piston II which is brought to rest in the manner previous- -ly described.

A modified form of the apparatus is shown in Figures 7, 8 and 9, the muzzle portion alone being illustrated. This modification is intended for punching holes in plates and for this purpose the previously described anchoring bolt is replaced by a short punch 28 which is attached to the piston II as before.

The muzzle cap 30 is relatively short and the copper disc 29 for arresting the piston is located near the muzzle end thereof, there being no additional water seal. Lateral ports or apertures II are provided for dissipating the pressures created when the punch 28 strikes the column of water within the cap. Figure 7 shows the required proportions of the cap to ensure that the piston is arrested at the proper time having regard to the depth of penetration of the punch. The energy of the piston is absorbed partly by shearing oi the copper ring 29 and partly by the shearing of the material of the piston itself as it enters the reduced bore of the muzzle cap. It will oi course be understood that the disc 29 may be of any material other than metal in which case it will act solely as a water seal and the arrest of the piston will be effected by shearing thereof as described.

Where it is desired to use a longer punch the length or the cap may be increased as indicated by the chain dotted lines in Figure 9, the lateral ports 3| being of course lengthened to a corre" sponding extent.

Another form of end sealing arrangement is shown in Figures 10 and 11 which represent the end of a muzzle cap 2 provided with a recess 32. A tapered plug 33 of fibre or other suitable sealing material as shown in Figure 12 is driven into the recess. The arrest of the piston is efl'ected by means of a copper or other disc as described in connection with the form shown in Figure 1.

It will be understood that numerous changes may be made in the details of the various forms of apparatus described and these are to be regarded as examples only. In particular the materials used for the different parts of theapparatus may be widely varied to suit the particular conditions encountered in practising the invention or as experience may direct.

I-claiin:

1. Apparatus of the kind referred to comprising a projection barrel adapted to the discharge of a projectile having a separable driving part and a driven part, means in the barrel for excluding water therefrom and for arresting the moving separable portion of the projectile, and a member extending beyond the arresting means and having lateral ports the inner sides of which terminate substantially at the said water excluding means. v

2. Apparatus of the kind referred to comprising a projection barrel adapted to the discharge of a projectile having a separable driving part and a driven part, means comprising a metal closure member in the barrel for arresting the separable part of the projectile, a tubular member forming an extension of the barrel beyond said closure member and formed with oppositely disposed lateral ports the inner sides of which terminate at a point adjacent said closure to afiord shockiess dispersal of water within the said extension when the projectile is fired.

3. Apparatus of the kind referred to comprising a projection barrel adapted to the discharge of a projectile having a separable driving part and a driven part, means for arresting the separable part of the projectile therein comprising a metal closure disc, an extension member removably secured to the barrel and having a smaller bore, said extension member being formed A with a pair of oppositely directed ports terminating at the said closure disc for the dispersal of pressure within the member.

' PERCY COX. 

